What large-scale, survey research tells us about teacher effects on student achievement: Insights from the prospects study of elementary schools

This paper discusses conceptual and methodological issues that a-rise when educational researchers use data from large-scale, survey research to examine the effects of teachers and teaching on student achievement. Using data from Prospects: The Congressionally Mandated Study of Educational Growth and Opportunity 1991-1994, we show that researchers' use of different statistical models has led to widely varying interpretations about the overall magnitude of teacher effects on student achievement. However, we conclude that in well-specified models of academic growth, teacher effects on elementary school students' growth in reading and mathematics achievement are substantial (with d-type effect sizes ranging from .72 to .85). We also conclude that various characteristics of teachers and their teaching account for these effects, including variation among teachers in professional preparation and content knowledge, use of teaching routines, and Patterns of content coverage, with effect sizes for variables measuring these characteristics of teachers and their teaching showing d-type effect sizes in the range of .10. The paper concludes with an assessment of the current state of the art in large-scale, survey research on teaching. Here, we conclude that survey researchers must simultaneously improve their measures of instruction while paying careful attention to issues of causal inference.